Process for producing olefin oxide

ABSTRACT

A process for producing an olefin oxide which comprises reacting an olefin with oxygen in the presence of a catalyst comprising (a) copper oxide, (b) ruthenium metal or ruthenium oxide and (c) alkaline metal component or alkaline earth metal component.

FIELD OF THE INVENTION

The present invention relates to a process for producing an olefinoxide.

BACKGROUND ART

Olefin oxides, such as propylene oxide, are important and versatileintermediates used in the production of a large variety of valuableconsumer products such as polyurethane foams, polymers, alkylene glycol,cosmetics, food emulsifiers and as fumigants and insecticides.

Previous research on olefin epoxidation involved the use of Ag-basedcatalysts (Appl. Catal. A. Gen. 2001, 221, 73.), as well as silicasupported Cu (J. Catal. 2005, 236, 401), various metal oxides (Appl.Catal. A. Gen. 2007, 316, 142), Au-based catalysts with H₂ as aco-reactant (Ind. & Eng. Chem. Res. 1995, 34, 2298, J. Catal. 1998, 178,566; Appl. Catal. A. Gen. 2000, 190, 43; Angew. Chem. Int. Ed. 2004, 43,1546), titania based catalysts that deactivated quickly (Catal. Commun.2001, 1356; Catal. Commun. 2003, 4, 385), molten salts of metal nitrates(Appl. Catal. A. Gen. 2000, 196, 217), the use of O₃ (Appl. Catal. A.Gen. 2000, 196, 217) and nitrous oxide (Ind. & Eng. Chem. Res. 1995, 34,2298) as reactants. Although these developments are scientificallyinteresting, they have serious drawbacks, such as low PO selectivitiesand/or low propylene conversions, short catalyst lifetimes, the use ofhigher pressures or the use of costly co-reactants (Appl. Catal. A. Gen.2007, 316, 142).

SUMMARY OF THE INVENTION

The present invention provides:

[1] A process for producing an olefin oxide which comprises reacting anolefin with oxygen in the presence of a catalyst comprising (a) copperoxide, (b) ruthenium metal or ruthenium oxide and (c) alkaline metalcomponent or alkaline earth metal component.[2] The process according to [1], wherein the catalyst comprises (d)halogen component.[3] The process according to [1], wherein (a) copper oxide, (b)ruthenium metal or ruthenium oxide and (c) alkaline metal component oralkaline earth metal component are supported on a porous support.[4] The process according to [2], wherein (a) copper oxide, (b)ruthenium metal or ruthenium oxide, (c) alkaline metal component oralkaline earth metal component and (d) halogen component are supportedon a porous support.[5] The process according to [3] or [4], wherein the porous supportcomprises Al₂O₃, SiO₂, TiO₂ or ZrO₂.[6] The process according to [3] or [4], wherein the porous supportcomprises SiO₂.[7] The process according to any one of [1] to [6], wherein the totalamount of (a) copper oxide, (b) ruthenium metal or rutheniumoxide and(c) alkaline metal component or alkaline earth metal component is 0.01to 80% by weight of the amount of the catalyst.[8] The process according to any one of [1] to [7], wherein thecopper/ruthenium metal molar ratio in the catalyst is 1/99 to 99/1.[9] The process according to any one of [1] to [8], wherein theruthenium/(c) component metal molar ratio in the catalyst is 1/99 to99/1.[10] The process according to any one of [1] to [9], wherein (a) copperoxide is CuO.[11] The process according to any one of [1] to [10], wherein (b)ruthenium metal or rutheniumoxide is RuO₂.[12] The process according to any one of [1] to [11], wherein (c)alkaline metal component or alkaline earth metal component is analkaline metal-containing compound.[13] The process according to any one of [1] to [12], wherein (c)alkaline metal component or alkaline earth metal component is asodium-containing compound.[14] The process according to [1] to [12], wherein (c) alkaline metalcomponent or alkaline earth metal component is a potassium-containingcompound.[15] The process according to [3], wherein the catalyst is obtained byimpregnating a porous support with a solution containing a copper ion, aruthenium ion and an alkaline metal or alkaline earth metal ion toprepare a composition, followed by calcining the composition.[16] The process according to [3] or [4], wherein the catalyst isobtained by impregnating a porous support with a solution containing acopper ion, a ruthenium ion, an alkaline metal or alkaline earth metalion and a halogen ion to prepare a composition, followed by calciningthe composition.[17] The process according to any one of [1] to [16], wherein the olefinis propylene and the olefin oxide is propylene oxide.[18] The process according to any one of [1] to [17], which comprisesreacting an olefin with oxygen at a temperature of 100 to 350° C.[19] A catalyst for production of an olefin oxide which comprises (a)copper oxide, (b) ruthenium metal or ruthenium oxide and (c) alkalinemetal component or alkaline earth metal component.[20] The catalyst according to [19] which comprises (d) halogencomponent.[21] The catalyst according to [19], wherein (a) copper oxide, (b)ruthenium metal or ruthenium oxide and (c) alkaline metal component oralkaline earth metal component are supported on a porous support.[22] The catalyst according to [20], wherein (a) copper oxide, (b)ruthenium metal or ruthenium oxide, (c) alkaline metal component oralkaline earth metal component and (d) halogen component are supportedon a porous support.[23] The catalyst according to [21] which is obtained by impregnating aporous support with a solution containing a copper ion, a ruthenium ionand an alkaline metal or alkaline earth metal ion to prepare acomposition, followed by calcining the composition.[24] The catalyst according to [21] or [22] which is obtained byimpregnating a porous support with a solution containing a copper ion, aruthenium ion, an alkaline metal or alkaline earth metal ion and halogenion to prepare a composition, followed by calcining the composition.[25] The catalyst according to any one of [19] to [24], wherein (c)alkaline metal component or alkaline earth metal component is analkaline metal-containing compound.[26] The catalyst according to [19] to [24], wherein (c) alkaline metalcomponent or alkaline earth metal component is a sodium-containingcompound.[27] The catalyst according to [19] to [24], wherein (c) alkaline metalcomponent or alkaline earth metal component is a potassium-containingcompound.[28] The catalyst according to any one of [21] to [27], wherein theporous support comprises Al₂O₃, SiO₂, TiO₂ or ZrO₂.[29] The catalyst according to anyone of [21] to [28], wherein theporous support comprises SiO₂.[30] The catalyst according to anyone of [19] to [29], wherein theolefin oxide is propylene oxide.[31] Use of a catalyst for producing an olefin oxide, said catalystcomprising (a) copper oxide, (b) ruthenium metal or ruthenium oxide and(c) alkaline metal component or alkaline earth metal component.[32] The use of a catalyst according to [31], wherein the olefin oxideis propylene oxide.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a graph showing the result of Example 1.

FIG. 2 is a graph showing the result of Example 2.

FIG. 3 is a graph showing the result of Example 3.

FIG. 4 is a graph showing the result of Example 4.

FIG. 5 is a graph showing the result of Example 5.

FIG. 6 is a graph showing the XRD patterns of Example 6.

DETAILED DESCRIPTION OF THE INVENTION

The process of the present invention comprises reacting an olefin withoxygen in the presence of a catalyst comprising (a) copper oxide, (b)ruthenium metal or ruthenium oxide and (c) alkaline metal component oralkaline earth metal component. In the catalyst, the components (a), (b)and (c) are preferably supported on a porous support. This catalyst isvaluable for production of olefin oxides, which is one aspect of thepresent invention.

The porous support has pores capable of supporting the components (a),(b) and (c). The porous support comprises preferably Al₂O₃, SiO₂, TiO₂,or ZrO₂, more preferably SiO₂. Examples of the porous support comprisingSiO₂ include mesoporous silica. Such a porous support may also comprisezeolites.

If the catalyst comprises SiO₂ as a support, olefin oxides can beprepared with good yield and good selectivity.

The catalyst may comprise one or more kinds of (a) copper oxide.

The (a) copper oxide is usually composed of copper and oxygen.

Examples of the copper oxide include Cu₂O and CuO. The copper oxide ispreferably CuO.

The catalyst may comprise one or more kinds of (b) ruthenium metal orruthenium oxide. The (b) ruthenium oxide is usually composed ofruthenium and oxygen. Examples of the ruthenium oxide include RuO₄, andRuO₂. The component (b) is preferably RuO₂.

The catalyst may comprise one or more kinds of (c) alkaline metalcomponent or alkaline earth metal component.

The component (c) may be an alkaline metal-containing compound, analkaline earth metal-containing compound, an alkaline metal ion or analkaline earth metal ion.

Examples of the alkaline metal-containing compound include compoundscontaining an alkaline metal such as Na, K, Rb and Cs. Examples of thealkaline earth metal-containing compound include compounds containing analkaline earth metal such as Ca, Mg, Sr and Ba. Examples of the alkalinemetal ion include Na⁺, K⁺, Rb⁺ and Cs⁺. Examples of the alkaline earthmetal ion include such as Ca²⁺, Mg²⁺, Sr²⁺ and Ba²⁺.

The component (c) is preferably an alkaline metal-containing compound,an alkaline metal or both of them, more preferably an alkalinemetal-containing compound, still more preferably a sodium-containingcompound or a potassium-containing compound.

When the compound (c) is a potassium-containing compound or potassiumion, preferably a potassium-containing compound, the olefin oxideselectivity is excellent at reaction temperature not more than 270° C.

The alkaline metal-containing compound and alkaline earthmetal-containing compound are preferably an alkaline metal salt and analkaline earth metal salt. The alkaline metal salt comprises thealkaline metal ion as mentioned above with an anion. The alkaline earthmetal salt comprises the alkaline earth metal ion as mentioned abovewith an anion. Examples of anions in such salts include Cl⁻, Br⁻, I⁻,NO₃ ⁻, SO₄ ²⁻ and CO₃ ²⁻. Such salts are preferably an alkaline metalsalt with a halogen, such as an alkaline metal halide, or an alkalineearth metal-containing salt with a halogen, such as an alkaline earthmetal halide, more preferably an alkaline metal salt with a halogen,still more preferably an alkaline metal chloride.

The catalyst comprises preferably CuO, RuO₂ and an alkalinemetal-containing compound, still more preferably CuO, RuO₂ and asodium-containing compound, because the olefin oxide yield andselectivity can be improved by adopting such combination to theproduction of an olefin oxide. Particularly if the catalyst comprisesNaCl, as the (c) component, it can show excellent olefin oxideselectivity and yield. The copper/ruthenium metal molar ratio in thecatalyst is preferably 1/99 to 99/1. When the metal molar ratio fallswithin such a range, the olefin oxide yield and selectivity can befurther improved. The lower limit of the molar ratio is more preferably2/98, still more preferably 3/97. The upper limit of the molar ratio ismore preferably 98/2, still more preferably 97/3.

The ruthenium/(c) component molar ratio in the catalyst is preferably1/99 to 99/1. When the molar ratio falls within such a range, the olefinoxide yield and selectivity can be further improved. The lower limit ofthe molar ratio is more preferably 2/98, still more preferably 3/97. Theupper limit of the molar ratio is more preferably 98/2, still morepreferably 97/3. The “(c) component” of the molar ratio represents thealkaline metal or alkaline earth metal existing in the (c) component andthe alkaline metal or alkaline earth metal ion existing in the (c)component.

When the components (a), (b) and (c) are supported on a porous supportin the catalyst, the total content of the components (a), (b) and (c) ispreferably 0.01 to 80% by weight of the amount of the catalyst. When thetotal content falls within such a range, the olefin oxide yield andselectivity can be further improved. The lower limit of the totalcontent is more preferably 0.05% by weight, still more preferably 0.1%by weight of the amount of the catalyst. The upper limit of the totalcontent is more preferably 50% by weight, still more preferably 30% byweight of the amount of the catalyst.

The catalyst may comprise (d) halogen component besides the components(a), (b) and (c). The component (d) is generally a halogen-containingcompound. Examples of the halogen include chlorine, fluorine, iodine andbromine.

Examples of such a halogen-containing compound include halides of copperor ruthenium and oxyhalides of copper or ruthenium. If the catalystcomprises the component (d), the component may be supported on theporous support as mentioned above.

Production of the catalyst is not restricted to a specific process,examples of which include the conventional methods.

When the components (a), (b) and (c) are supported on a porous supportin the catalyst, the catalyst can be obtained by impregnating a poroussupport with a solution containing a copper ion, a ruthenium ion and analkaline metal or alkaline earth metal-containing ion to prepare acomposition, followed by calcining the composition. The support can bein form of powder, or shaped to a desired structure as necessary. If thecatalyst comprises component (c) which is an alkaline metal salt with ahalogen or alkaline earth metal salt with a halogen, and the component(d) supported on the porous support, the catalyst can be obtained in thesame procedure as mentioned above except that solution contains copperion, a ruthenium ion, an alkaline metal or alkaline earthmetal-containing ion and a halogen ion.

The solution containing a copper ion, a ruthenium ion and an alkalinemetal or alkaline earth metal ion can be prepared by dissolving a coppermetal salt, a ruthenium metal salt and an alkaline metal or alkalineearth metal salt in a solvent. Examples of the copper metal salt includecopper acetate, copper ammonium chloride, copper bromide, coppercarbonate, copper ethoxide, copper hydroxide, copper iodide, copperisobutyrate, copper isopropoxide, copper oxalate, copper oxychloride,copper nitrates, and copper chlorides. Examples of the ruthenium metalsalt include, for example, a halide such as ruthenium bromide, rutheniumchloride, ruthenium iodide, an oxyhalide such as Ru₂OCl₄, Ru₂OCl₅ andRu₂OC₁₆, a halogeno complex such as [RuCl₂(H₂O)₄]Cl, an ammine complexsuch as [Ru(NH₃)₅H₂O]Cl₂, [Ru(NH₃)₅Cl]Cl₂, [Ru(NH₃)₆]Cl₂ and[Ru(NH₃)₆]Cl₃, a carbonyl complex such as Ru(CO)₅ and Ru₃(CO)₁₂, acarboxylate complex such as [Ru₃O(OCOCH₃)₆(H₂O)₃], rutheniumnitrosylchloride, and [Ru₂(OCOR)₄]Cl (R=alkyl group having 1 to 3 carbonatoms), a nitrosyl complex such as [Ru(NH₃)₅(NO)]Cl₃,[Ru(OH)(NH₃)₄(NO)](NO₃)₂ and [Ru(NO)](NO₃)₃, an amine complex, anacetylacetonate complex, and ammonium salt such as (NH₄)₂RuCl₆. Thealkaline metal or alkaline earth metal salt for the solution may be thesame as or different from the (c) component. Examples of the alkalinemetal or alkaline earth metal salt include alkaline metal nitrates,alkaline earth metal nitrates, alkaline metal halides and alkaline earthmetal halides, preferably alkaline metal halides and alkaline metalnitrates, more preferably NaNO₃, NaCl, KCl and KNO₃. At least one of themetal salts for the solvent contains preferably a halogen ion, morepreferably a chloride ion. Such a halogen ion may form the (c) componentsuch as NaCl and the (d) component such as halides and oxyhalides of Cuor Ru. The solution may contain acidic or basic compounds in order tocontrol its pH.

The acid compound may be any of an inorganic acid and an organic acid.Examples of the inorganic acid include hydrochloric acid, nitric acid,nitrous acid and perchloric acid etc. Examples of the organic acidinclude aliphatic carboxylic acids such as acetic acid, oxalic acid,propionic acid, butyric acid, citric acid, maleic acid, fumaric acid andtartaric acid etc.; and aromatic carboxylic acids such as benzoic acid,dicarboxybenzene, tricarboxybenzene, dicarboxynaphthalene anddicarboxyanthracene etc.

Examples of the base compound include alkaline metal hydroxides, aminecompounds, imine compounds, hydrazine or hydrazine compounds, ammonia,hydroxylamine, hydroxyamine and ammonium hydroxides.

Examples of the alkaline metal hydroxides include sodium hydroxide,potassium hydroxide etc. Examples of the amine compounds includealiphatic amines having a carbon number of 1 to 20 and aromatic amineshaving a carbon number of 6 to 20, such as methylamine, ethylamine,propylamine, butylamine, amylamine, hexylamine, heptylamine, octylamine,decylamine, dodecylamine, stearylamine, dimethylamine, diethylamine,dipropylamine, dibutylamine, trimethylamine, triethylamine,ethanolamine, dimethylethanolamine, diethylethanolamine,triethanolamine, ethylenediamine, tetramethylenediamine,pentamethylenediamine, diethylenetriamine, aniline, benzyamine andphenylenediamine etc.

Examples of the imine compounds include ethyleneimine, pyrrolidine,piperidine and piperazine etc. Examples of the amide compounds includeacetamide and benzamide etc. Examples of the hydrazine compounds includemethylhydrazine and phenylhydrazine etc. Examples of the quaternaryammonium salts include quaternary ammonium hydroxides such astetramethylammonium hydroxide, tetraethylammonium hydroxide,tetrapropylammonium hydroxide etc.; quaternary ammonium halides such astetramethylammonium chloride, tetramethylammonium bromide,tetraethylammonium chloride, and tetraethylammonium bromide etc.; etc.

Examples of the solvent for the solution include water and alcohols suchas methanol or ethanol.

The total amount of the porous support is preferably 20 to 99.99% byweight, more preferably 50 to 99.5% by weight, still preferably 70 to99.9% by weight of the catalyst as obtained.

The composition as prepared by the impregnation is preferably dried at atemperature of approximately 40° C. to approximately 200° C. beforecalcining the composition. Drying may be performed under an atmosphereof air or also under an inert gas atmosphere (for example, Ar, N₂, He)at standard pressure or reduced pressure. A drying time is preferably inthe range from 0.5 to 24 hours. After drying, the composition can beshaped to a desired structure as necessary.

Calcining the composition is not limited, but preferably may beperformed under a gas atmosphere containing oxygen. Examples of such agas stream include air and an oxygen gas. The gas may be used afterbeing mixed at an appropriate ratio with a diluting gas such asnitrogen, helium, argon, and water vapor. An optimal temperature forcalcination varies depending on the kind of the gas and the composition,however, a too high temperature may cause agglomeration of rutheniumoxide and copper oxide. Accordingly, the calcination temperature istypically 200 to 800° C., preferably 400 to 600° C.

The catalyst can be used as powder, but it is usual to shape it intodesired structures such as spheres, pellets, cylinders, rings, hollowcylinders or stars. The catalyst can be shaped by a known procedure suchas extrusion, ram extrusion, tableting. The calcination is normallyperformed after shaping into the desired structures, but it can also beperformed before shaping them.

Next, the following explains a reaction of an olefin with oxygen in thepresence of the catalyst as described above.

In the present invention, the olefin may have a linear or branchedstructure and contains usually 2 to 10, preferably 2 to 8 carbon atoms.The olefin may be a monoolefin or a diolefin. Examples of the monoolefininclude ethylene, propylene, butene, pentene, hexene, heptene, octene,nonene, and decene. Examples of the diene include butadiene such as1,3-butadiene or 1,2-butadiene. Examples of the olefin includepreferably monoolefin, more preferably ethylene, propylene, butene,pentene, hexene, heptene and octene, still more preferably ethylene,propylene and butene, most preferably propylene.

The reaction is generally performed in the gas phase. In the reaction,the olefin and oxygen may be fed respectively in the form of a gas.Olefin and oxygen gases can be fed in the form of their mixed gas.Olefin and oxygen gases may be fed with diluent gases. Examples ofdiluent gases include nitrogen, methane, ethane, propane, carbondioxide, or rare gases, such as argon and helium.

As the oxygen source, pure oxygen may be used, or a mixed gas containinga gas inactive to the reaction, such as air, may be used. The amount ofoxygen used varies depending on the reaction type, the catalyst, thereaction temperature or the like. The amount of oxygen is typically 0.01to 100 mol, and preferably 0.03 to 30 mol, and more preferably 0.25 to10 mol, with respect to 1 mol of the olefin.

The reaction is performed at a temperature generally of 100 to 350° C.,preferably of 120 to 330° C., more preferably of 170 to 310° C., stillmore preferably of 200 to 270° C. In particular, the reactiontemperature is most preferably 240 to 270° C. for the reaction in amicroreactor.

The reaction is usually carried out under reaction pressure in the rangeof reduced pressure to increased pressure. By carrying out the reactionunder such a reaction pressure condition, the productivity andselectivity of olefin oxides can be improved. Reduced pressure means apressure lower than atmospheric pressure. Increased pressure means apressure higher than atmospheric pressure. The pressure is typically inthe range of 0.01 to 3 MPa, and preferably in the range of 0.02 to 2MPa, in the absolute pressure.

The reaction may be carried out as a batch reaction or a continuousreaction, preferably as a continuous reaction for industrialapplication. The reaction of the present invention may be carried out bymixing an olefin and oxygen and then contacting the mixture with thecatalyst under reduced pressure to the increased pressure.

The reactor type is not limited. Examples of the reactor type are fluidbed reactor, fixed bed reactor, moving bed reactor, and the like,preferably fixed bed reactor. In the case of using fixed bed reactor,single tube reactor or multi tube reactor can be employed. More than onereactor can be used. If the number of reactors is large, small reactorsas for example microreactors, can be used, which can have multiplechannels. Adiabatic type or heat exchange type may also be used.

In the present invention, the olefin oxide may have a linear or branchedstructure and contains usually 2 to 10, preferably 2 to 8 carbon atoms.The olefin oxide may have one carbon-carbon double bond when thediolefin is applied for the reaction. Examples of the olefin oxidehaving one carbon-carbon double bond include 3,4-epoxy-1-butene.Examples of the olefin oxides include preferably ethylene oxide,propylene oxide, butene oxide, pentene oxide, hexene oxide, hepteneoxide and octene oxide, more preferably ethylene oxide, propylene oxideand butene oxide, still more preferably propylene oxide.

The olefin oxide as obtained can be collected by a method known in theart such as separation by distillation.

EXAMPLES

In Examples 1 to 5, each measurement was performed according to thefollowing method:

Data analysis for sample gases was conducted by an on-line Micro-GasChromatograph (Varian, CP-4900) equipped with a thermal conductivitydetector (TCD), PoraPLOT U (10M) and Molecular sieve 13X (10M).

The detected products were propylene oxide (PO), acetone (AT),acetaldehyde (AD), CO_(x) (CO₂ and CO), and propanal+acrolein (PaL+AC).

The propylene conversion, product selectivity, and yield (calculated asselectivity of product×propylene conversion) of products were calculatedon the basis of carbon balance. Propylene conversions (X_(PR)) weredetermined from the following:

X_(PR)={[PO+AC+AT+2AD/3+CO₂/3]_(out)/[C₃H₆]_(in)}×100%;

and PO selectivities (S_(PO)) were then calculated using the followingexpression:

S_(PO)={[PO]/[PO+AC+AT+2AD/3+CO₂/3]}×100%

Note: PaL+AC are reported together since the two compounds appear at thesame retention time, although the PaL is typically only found in traceamounts.

Example 1

Aqueous solutions of Ru[(NH₄)₂RuCl₆, Aldrich] and Cu [Cu(NO₃)₂, AlfaAesar, ACS, 98.0%-102.0%] and Na[NaNO₃, Alfa Aesar, ACS, 99.0%] weremixed at a metal weight ratio of 4:2:1 (=Ru:Cu:Na), to prepare a metalsalt solution for achieving 12.5 wt % (by metal atomic weight, relativeto the amount of the catalyst) loading on a SiO₂ support powder (surfacearea 145 m²/g). The metal salt solution was then allowed to impregnatethe support for 24 hours in air. The resulting material was then heatedat 150° C. until dried, and calcined at 500° C. for 12 hours in air.

The catalyst (5.0 mg) was placed in a well of a reactor as mentioned inAngew. Chem. Int. Ed. 38 (1999) 2794, equipped with array microreactors,wells along each reactor channel and a passivated 200 micron IDcapillary sampling probe within the reactor channel. The mixture gasconsisting of 1 vol % propylene (C₃H₆), 4 vol % O₂, and 95 vol % He wasfed to the well containing the catalyst, at a gas hourly space velocity(GHSV) of 20,000 h⁻¹, at a reactor temperature of 190, 210, 230, 250,260, 270, 290 or 310° C.

Gas sampling was accomplished by withdrawing reactor exit gases usingthe passivated 200 micron ID capillary sampling probe.

The results are shown in FIG. 1.

Example 2

The catalysts were prepared in the same manner as Example 1, except thatthe total metal content in the catalyst was 8% by weight. Propyleneoxide was prepared in the same manner as Example 1 except that thecatalysts of the present example were used, the reactor temperature was250° C., and GHSV was changed.

The results are shown in FIG. 2.

Example 3

The catalysts were prepared in the same manner as Example 1, except thatthe total metal content in each of the catalysts was 5, 7, 10 or 12.5%by weight. Propylene oxide was prepared in the same manner as Example 1except that the catalysts of the present example were used and thereactor temperature was 250° C.

The results are shown in FIG. 3.

Example 4

The catalysts were prepared in the same manner as Example 3, except thatthe total metal content in the catalysts was 12.5% by weight. Propyleneoxide was prepared in the same manner as Example 3 except that theoxygen/propylene (volume ratio) was changed.

The results are shown in FIG. 4.

Example 5

Time-on-stream testing was conducted with the catalyst. The catalyst wasprepared in the same manner as Example 4. Propylene oxide was preparedin the same manner as Example 3 except that the reactor temperature was250° C. or 265° C.

The results are shown in FIG. 5.

Example 6

The powder x-ray diffraction pattern of the catalyst obtained in Example1 was determined with PANalytical X'Pert PRO fitted with a Ni filter anda Soller slit collimator.

The Cu—K_(α) radiation at 45 kV and 40 mA was used to identify theactive catalyst phase.

The following compositions were also examined in the same manner, Na₂O(1.8 wt % Na, relative to the total of Na₂O and SiO₂) supported on SiO₂which was prepared from NaNO₃; CuO (3.6 wt % Cu, relative to the totalof CuO and SiO₂) supported on SiO₂ which was prepared from Cu(NO₃)₂;RuO₂ (7.2 wt % Ru, relative to the total of RuO₂ and SiO₂) supported onSiO₂ which was prepared from (NH₄)₂RuCl₆; NaCl (1.8 wt % Na, relative tothe total of NaCl and SiO₂) supported on SiO₂ which was prepared fromNaCl; and bimetallic RuO₂+CuO supported on SiO₂ which was prepared inthe same manner as the catalyst except that NaCl was not used.

The XRD patterns are shown in FIG. 6. The XRD pattern of the catalystshows that the catalyst comprises CuO, RuO₂ and NaCl without forming anycrystalline mixed metal oxides or alloys.

Example 7

A catalyst is prepared in the same manner as Example 1, except that TiO₂is used instead of SiO₂. Production of propylene oxide is carried out inthe same manner as Example 1 except that the catalyst of the presentexample is used.

In Examples 8 to 15, data analysis was performed according to thefollowing method:

A reaction gas was mixed with ethane (10 Nml/min) as an externalstandard, and then directly introduced into the TCD-GC equipped with acolumn of Gaskuropack 54 (2 m). All products in the reaction gas werecollected for 1 hour with double methanol traps connected in series andcooled with a dry-ice/methanol bath. The two methanol solutions weremixed together and added to anisole as an external standard, and thenanalyzed with two FID-GCs equipped with different columns, PoraBOND U(25 m) and PoraBOND Q (25 m).

The propylene conversion, product selectivity, and yield of productswere calculated in the same manner as Examples 1 to 5.

Example 8

The metal composition was prepared by a co-impregnation method. Apredetermined weight (1.9 g) of an amorphous silica powder (SiO₂, JapanAerosil, 380 m²/g) was added to an aqueous solution mixture containing0.54 g of (NH₄)₂RuCl₆ (Aldrich), 0.30 g of Cu(NO₃)₂ of (Wako) and 0.10 gNaNO, (Wako), followed by stirring for 24 hours in the air to impregnatethe support with the metal salts. The resulting material was then heatedat 100° C. until dried, and calcined at 500° C. for 12 hours in the airto give a catalyst.

The catalyst was evaluated by using a fixed-bed reactor. Filling a½-inch reaction tube made of stainless steel with 1 mL of the thusobtained catalyst, the following gases were fed to the reaction tube tocarry out the reaction: 450 NmL/h of propylene, 900 NmL/h of the air,990 NmL/h of a nitrogen gas. Such a reaction was carried out at thereaction temperature of 200° C. under the increased pressure (equivalentto 0.3 MPa in the absolute pressure).

The result is shown in Table 1.

Example 9

The preparation and the reaction were conducted in the same manner asExample 8, except that the preparation was conducted using 0.64 g of(NH₄)₂RuCl₆ (Aldrich), 0.35 g of Cu(NO₃)₂ (Wako), 0.08 g of Rb(NO₃)(Wako) and 2.3 g of an amorphous silica powder (SiO₂, Japan Aerosil, 380m²/g) as raw materials.

The result is shown in Table 1.

Example 10

The preparation and the reaction were conducted in the same manner asExample 8, except that the preparation was conducted using 0.76 g of(NH₄)₂RuCl₆ (Aldrich), 0.42 g of Cu(NO₃)₂ (Wako), 0.08 g of Cs(NO₃)(Wako) and 2.7 g of an amorphous silica powder (SiO₂, Japan Aerosil, 380m²/g) as raw materials.

The result is shown in Table 1.

Example 11

The preparation and the reaction were conducted in the same manner asExample 8, except that the preparation was conducted using 0.23 g of(NH₄)₂RuCl₆ (Aldrich), 0.13 g of Cu(NO₃)₂ (Wako), 0.1 g of Mg(NO₃)₂(Wako) and 0.8 g of an amorphous silica powder (SiO₂, Japan Aerosil, 380m²/g) as raw materials.

The result is shown in Table 1.

Example 12

The preparation and the reaction were conducted in the same manner asExample 8, except that the preparation was conducted using 1.0 g of(NH₄)₂RuCl₆ (Aldrich), 0.58 g of Cu(NO₃)₂ (Wako), 0.08 g of Ca(NO₃)₂(Wako) and 3.7 g of an amorphous silica powder (SiO₂, Japan Aerosil, 380m²/g) as raw materials. The result is shown in Table 1.

Example 13

The preparation and the reaction were conducted in the same manner asExample 8, except that the preparation was conducted using 0.86 g of(NH₄)₂RuCl₆ (Aldrich), 0.47 g of Cu(NO₃)₂ (Wako), 0.15 g of Sr(NO₃)₂(Wako) and 3.0 g of an amorphous silica powder (SiO₂, Japan Aerosil, 380m²/g) as raw materials.

The result is shown in Table 1.

Example 14

The preparation and the reaction were conducted in the same manner asExample 8, except that the preparation was conducted using 0.73 g of(NH₄)₂RuCl₆ (Aldrich), 0.40 g of Cu(NO₃)₂ (Wako), 0.10 g of Ba(NO₃)₂(Wako) and 2.6 g of amorphous silica powder (SiO₂, Japan Aerosil, 380m²/g) as raw materials.

The result is shown in Table 1.

TABLE 1 Example 8 9 10 11 12 13 14 alkaline metal or Na Rb Cs Mg Ca SrBa alkaline earth metal reaction temperature 200 200 200 200 200 200 200(° C.) propylene conversion 0.7 0.6 0.3 0.6 0.4 0.4 0.5 (%) propyleneoxide 22 13 8 5 8 7 9 selectivity (%)

Example 15

A catalyst is prepared in the same manner as Example 8, except that TiO₂is used instead of SiO₂. Production of propylene oxide is carried out inthe same manner as Example 8 except that the catalyst of the presentexample is used.

Examples 16-18

The metal composition was prepared by a co-impregnation method. Apredetermined weight (1.9 g) of an amorphous silica powder (SiO₂, JapanAerosil, 380 m²/g) was added to an aqueous solution mixture containing0.54 g of (NH₄)₂RuCl₆ (Aldrich), 0.30 g of Cu(NO₃)₂ (Wako) and 0.10 g ofKNO₃ (Wako), followed by stirring for 24 hours in the air to impregnatethe support with the metal salts. The resulting material was then heatedat 100° C. until dried, and calcined at 500° C. for 12 hours in the airto give a catalyst.

The catalyst was evaluated by using a fixed-bed reactor, Filling a½-inch reaction tube made of stainless steel with 1 mL of the thusobtained catalyst, the following gases were fed to the reaction tube tocarry out the reaction: 450 NmL/h of propylene, 900 NmL/h of the air,990 NmL/h of a nitrogen gas, Such a reaction was carried out at thereaction temperature of 200° C., 250° C. or 270° C. under the increasedpressure (equivalent to 0.3 MPa in the absolute pressure).

The result is shown in Table 2.

TABLE 2 Example 16 17 18 alkaline metal K K K reaction temperature 200250 270 (° C.) propylene conversion (%) 0.8 3.3 3.5 propylene oxide 8 1315 selectivity (%) STY* 17 102 126 *STY, i.e., space time yield,represents “(The amount of propylene oxide (μmol)/{the amount ofcatalyst(ml)*hour}”.

Example 19

The preparation and the reaction are conducted in the same manner asExample 8, except that 1,3-butadiene is used instead of propylene togive 3,4-epoxy-butene.

1. A process for producing an olefin oxide which comprises reacting anolefin with oxygen in the presence of a catalyst comprising (a) copperoxide, (b) ruthenium metal or ruthenium oxide and (c) alkaline metalcomponent or alkaline earth metal component.
 2. The process according toclaim 1, wherein the catalyst comprises (d) halogen component.
 3. Theprocess according to claim 1, wherein (a) copper oxide, (b) rutheniummetal or ruthenium oxide and (c) alkaline metal component or alkalineearth metal component are supported on a porous support.
 4. The processaccording to claim 2, wherein (a) copper oxide, (b) ruthenium metal orruthenium oxide, (c) alkaline metal component or alkaline earth metalcomponent and (d) halogen component are supported on a porous support.5. The process according to claim 3 or 4, wherein the porous supportcomprises Al₂O₃, SiO₂, TiO₂ or ZrO₂.
 6. The process according to claim 3or 4, wherein the porous support comprises SiO₂.
 7. The processaccording to claim 1 or 2, wherein the total amount of (a) copper oxide,(b) ruthenium metal or rutheniumoxide and (c) alkaline metal componentor alkaline earth metal component is 0.01 to 80% by weight of the amountof the catalyst.
 8. The process according to claim 1 or 2, wherein thecopper/ruthenium metal molar ratio in the catalyst is 1/99 to 99/1. 9.The process according to claim 1 or 2, wherein the ruthenium/(c)component metal molar ratio in the catalyst is 1/99 to 99/1.
 10. Theprocess according to claim 1 or 2, wherein (a) copper oxide is CuO. 11.The process according to claim 1 or 2, wherein (b) ruthenium metal orrutheniumoxide is RuO₂.
 12. The process according to claim 1 or 2,wherein (c) alkaline metal component or alkaline earth metal componentis an alkaline metal-containing compound.
 13. The process according toclaim 1 or 2, wherein (c) alkaline metal component or alkaline earthmetal component is a sodium-containing compound.
 14. The processaccording to claim 1 or 2, wherein (c) alkaline metal component oralkaline earth metal component is a potassium-containing compound. 15.The process according to claim 3, wherein the catalyst is obtained byimpregnating a porous support with a solution containing a copper ion, aruthenium ion and an alkaline metal or alkaline earth metal ion toprepare a composition, followed by calcining the composition.
 16. Theprocess according to claim 3 or 4, wherein the catalyst is obtained byimpregnating a porous support with a solution containing a copper ion, aruthenium ion, an alkaline metal or alkaline earth metal ion and ahalogen ion to prepare a composition, followed by calcining thecomposition.
 17. The process according to claim 1 or 2, wherein theolefin is propylene and the olefin oxide is propylene oxide.
 18. Theprocess according to claim 1 or 2, which comprises reacting an olefinwith oxygen at a temperature of 100 to 350° C.
 19. A catalyst forproduction of an olefin oxide which comprises (a) copper oxide, (b)ruthenium metal or ruthenium oxide and (c) alkaline metal component oralkaline earth metal component.
 20. The catalyst according to claim 19,which comprises (d) halogen component.
 21. The catalyst according toclaim 19, wherein (a) copper oxide, (b) ruthenium metal or rutheniumoxide and (c) alkaline metal component or alkaline earth metal componentare supported on a porous support.
 22. The catalyst according to claim20, wherein (a) copper oxide, (b) ruthenium metal or ruthenium oxide,(c) alkaline metal component or alkaline earth metal component and (d)halogen component are supported on a porous support.
 23. The catalystaccording to claim 21 which is obtained by impregnating a porous supportwith a solution containing a copper ion, a ruthenium ion and an alkalinemetal or alkaline earth metal ion to prepare a composition, followed bycalcining the composition.
 24. The catalyst according to claim 21 or 22which is obtained by impregnating a porous support with a solutioncontaining a copper ion, a ruthenium ion, an alkaline metal or alkalineearth metal ion and a halogen ion to prepare a composition, followed bycalcining the composition.
 25. The catalyst according to claim 19 or 20,wherein (c) alkaline metal component or alkaline earth metal componentis an alkaline metal-containing compound.
 26. The catalyst according toclaim 19 or 20, wherein (c) alkaline metal component or alkaline earthmetal component is a sodium-containing compound.
 27. The catalystaccording to claim 19 or 20, wherein (c) alkaline metal component oralkaline earth metal component is a potassium-containing compound. 28.The catalyst according to claim 21 or 22, wherein the porous supportcomprises Al₂O₃, SiO₂, TiO₂ or ZrO₂.
 29. The catalyst according to claim21 or 22, wherein the porous support comprises SiO₂.
 30. The catalystaccording to claim 19 or 20, wherein the olefin oxide is propyleneoxide.
 31. Use of a catalyst for producing an olefin oxide, saidcatalyst comprising (a) copper oxide, (b) ruthenium metal or rutheniumoxide and (c) alkaline metal component or alkaline earth metalcomponent.
 32. The use of a catalyst according to claim 31, wherein theolefin oxide is propylene oxide.